[ViewVC] Diff of: cvs/gvpe/src/vpn

Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs.
Revision 1.36 by pcg, Thu Mar 17 22:24:31 2005 UTC

…		…
25		25
26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.	26	// dns processing is EXTREMELY ugly. For obvious(?) reasons.
27	// it's a hack, use only in emergency situations please.	27	// it's a hack, use only in emergency situations please.
28		28
29	#include <cstring>	29	#include <cstring>
		30	#include <cassert>
30		31
31	#include <sys/types.h>	32	#include <sys/types.h>
32	#include <sys/socket.h>	33	#include <sys/socket.h>
33	#include <sys/wait.h>	34	#include <sys/wait.h>
34	#include <sys/uio.h>	35	#include <sys/uio.h>
…		…
43		44
44	#include "netcompat.h"	45	#include "netcompat.h"
45		46
46	#include "vpn.h"	47	#include "vpn.h"
47		48
48	#define MIN_RETRY 1.	49	#define MAX_POLL_INTERVAL 5. // how often to poll minimally when the server has no data
49	#define MAX_RETRY 60.	50	#define ACTIVITY_INTERVAL 5.
50		51
		52	#define TIMEOUT_FACTOR 8.
		53
		54	#define INITIAL_TIMEOUT 0.1 // retry timeouts
		55	#define INITIAL_SYN_TIMEOUT 2. // retry timeout for initial syn
		56
		57	#define MIN_SEND_INTERVAL 0.001 // wait at least this time between sending requests
		58	#define MAX_SEND_INTERVAL 2. // optimistic?
		59
		60	#define LATENCY_FACTOR 0.5 // RTT * LATENCY_FACTOR == sending rate
51	#define MAX_OUTSTANDING 400 // max. outstanding requests	61	#define MAX_OUTSTANDING 100 // max. outstanding requests
52	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING	62	#define MAX_WINDOW 1000 // max. for MAX_OUTSTANDING, and backlog
53	#define MAX_RATE 10000 // requests/s
54	#define MAX_BACKLOG (10*1024) // size of protocol backlog, must be > MAXSIZE	63	#define MAX_BACKLOG (64*1024) // size of gvpe protocol backlog (bytes), must be > MAXSIZE
55		64
56	#define MAX_DOMAIN_SIZE 220 // 255 is legal limit, but bind doesn't compress well	65	#define MAX_DOMAIN_SIZE 240 // 255 is legal limit, but bind doesn't compress well
57	// 240 leaves about 4 bytes of server reply data	66	// 240 leaves about 4 bytes of server reply data
58	// every two request byte sless give room for one reply byte	67	// every request byte less give room for two reply bytes
59		68
60	// seqno has 12 bits (3 bytes a 4 bits in the header)
61	#define SEQNO_MASK 0x7fff	69	#define SEQNO_MASK 0x3fff
62	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )	70	#define SEQNO_EQ(a,b) ( 0 == ( ((a) ^ (b)) & SEQNO_MASK) )
63		71
64	#define MAX_LBL_SIZE 63	72	#define MAX_LBL_SIZE 63
65	#define MAX_PKT_SIZE 512	73	#define MAX_PKT_SIZE 512
66		74
		75	#define RR_TYPE_A 1
		76	#define RR_TYPE_NULL 10
67	#define RR_TYPE_TXT 16	77	#define RR_TYPE_TXT 16
68	#define RR_TYPE_ANY 255	78	#define RR_TYPE_ANY 255
		79
69	#define RR_CLASS_IN 1	80	#define RR_CLASS_IN 1
		81
		82	#define CMD_IP_1 207
		83	#define CMD_IP_2 46
		84	#define CMD_IP_3 236
		85	#define CMD_IP_RST 29
		86	#define CMD_IP_SYN 113
		87	#define CMD_IP_REJ 32
70		88
71	// works for cmaps up to 255 (not 256!)	89	// works for cmaps up to 255 (not 256!)
72	struct charmap	90	struct charmap
73	{	91	{
74	enum { INVALID = (u8)255 };	92	enum { INVALID = (u8)255 };
…		…
154	return dec_len [len];	172	return dec_len [len];
155	}	173	}
156		174
157	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)	175	unsigned int basecoder::encode (char dst, u8 src, unsigned int len)
158	{	176	{
159	if (!len)	177	if (!len \|\| len > MAX_DEC_LEN)
160	return 0;	178	return 0;
161		179
162	int elen = encode_len (len);	180	int elen = encode_len (len);
163		181
164	mp_limb_t m [MAX_LIMBS];	182	mp_limb_t m [MAX_LIMBS];
…		…
183	return elen;	201	return elen;
184	}	202	}
185		203
186	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)	204	unsigned int basecoder::decode (u8 dst, char src, unsigned int len)
187	{	205	{
188	if (!len)	206	if (!len \|\| len > MAX_ENC_LEN)
189	return 0;	207	return 0;
190		208
191	u8 src_ [MAX_ENC_LEN];	209	u8 src_ [MAX_ENC_LEN];
192	unsigned int elen = 0;	210	unsigned int elen = 0;
193		211
…		…
240	}	258	}
241	abort ();	259	abort ();
242	}	260	}
243	#endif	261	#endif
244		262
245	// the following sequence has been crafted to	263	//static basecoder cdc64 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI-");
246	// a) look somewhat random
247	// b) the even (and odd) indices never share the same character as upper/lowercase
248	// the "_" is not valid but widely accepted (all octets should be supported, but let's be conservative)
249	// the other sequences are obviously derived
250	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	264	//static basecoder cdc63 ("_dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
251	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");	265	static basecoder cdc62 ("dDpPhHzZrR06QqMmjJkKBb34TtSsvVlL81xXaAeEFf92WwGgYyoO57UucCNniI");
252	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet	266	//static basecoder cdc36 ("dphzr06qmjkb34tsvl81xaef92wgyo57ucni"); // unused as of yet
253	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");	267	static basecoder cdc26 ("dPhZrQmJkBtSvLxAeFwGyO");
254		268
255	/////////////////////////////////////////////////////////////////////////////	269	/////////////////////////////////////////////////////////////////////////////
256		270
257	#define HDRSIZE 6	271	#define HDRSIZE 6
258		272
259	inline void encode_header (char *data, int clientid, int seqno)	273	inline void encode_header (char *data, int clientid, int seqno, int retry = 0)
260	{	274	{
261	u8 hdr[3] = { clientid, seqno >> 8, seqno };	275	seqno &= SEQNO_MASK;
		276
		277	u8 hdr[3] = {
		278	clientid,
		279	(seqno >> 8) \| (retry << 6),
		280	seqno,
		281	};
262		282
263	assert (clientid < 256);	283	assert (clientid < 256);
264		284
265	cdc26.encode (data, hdr, 3);	285	cdc26.encode (data, hdr, 3);
266	}	286	}
…		…
269	{	289	{
270	u8 hdr[3];	290	u8 hdr[3];
271		291
272	cdc26.decode (hdr, data, HDRSIZE);	292	cdc26.decode (hdr, data, HDRSIZE);
273		293
274	printf ("DEC %02x %02x %02x %02x\n", hdr[0], hdr[1], hdr[2], hdr[3]);
275
276	clientid = hdr[0];	294	clientid = hdr[0];
277	seqno = (hdr[1] << 8) \| hdr[2];	295	seqno = ((hdr[1] << 8) \| hdr[2]) & SEQNO_MASK;
278	}	296	}
279		297
280	/////////////////////////////////////////////////////////////////////////////	298	/////////////////////////////////////////////////////////////////////////////
281		299
282	struct byte_stream	300	struct byte_stream
…		…
311	}	329	}
312		330
313	void byte_stream::remove (int count)	331	void byte_stream::remove (int count)
314	{	332	{
315	if (count > fill)	333	if (count > fill)
316	abort ();	334	assert (count <= fill);
317		335
318	memmove (data, data + count, fill -= count);	336	memmove (data, data + count, fill -= count);
319	}	337	}
320		338
321	bool byte_stream::put (u8 *data, unsigned int datalen)	339	bool byte_stream::put (u8 *data, unsigned int datalen)
…		…
334	return false;	352	return false;
335		353
336	data [fill++] = pkt->len >> 8;	354	data [fill++] = pkt->len >> 8;
337	data [fill++] = pkt->len;	355	data [fill++] = pkt->len;
338		356
339	memcpy (data + fill, &((*pkt)[0]), pkt->len); fill += pkt->len;	357	memcpy (data + fill, pkt->at (0), pkt->len); fill += pkt->len;
340		358
341	return true;	359	return true;
342	}	360	}
343		361
344	vpn_packet *byte_stream::get ()	362	vpn_packet *byte_stream::get ()
345	{	363	{
		364	unsigned int len;
		365
		366	for (;;)
		367	{
346	int len = (data [0] << 8) \| data [1];	368	len = (data [0] << 8) \| data [1];
347		369
348	if (len > MAXSIZE && fill >= 2)	370	if (len <= MAXSIZE \|\| fill < 2)
349	abort (); // TODO handle this gracefully, connection reset	371	break;
350		372
		373	// TODO: handle this better than skipping, e.g. by reset
		374	slog (L_DEBUG, _("DNS: corrupted packet stream skipping a byte..."));
		375	remove (1);
		376	}
		377
351	if (fill < len + 2)	378	if (fill < len + 2)
352	return 0;	379	return 0;
353		380
354	vpn_packet *pkt = new vpn_packet;	381	vpn_packet *pkt = new vpn_packet;
355		382
356	pkt->len = len;	383	pkt->len = len;
357	memcpy (&((*pkt)[0]), data + 2, len);	384	memcpy (pkt->at (0), data + 2, len);
358	remove (len + 2);	385	remove (len + 2);
359		386
360	return pkt;	387	return pkt;
361	}	388	}
362		389
363	/////////////////////////////////////////////////////////////////////////////	390	/////////////////////////////////////////////////////////////////////////////
364		391
365	#define FLAG_QUERY ( 0 << 15)	392	#define FLAG_QUERY ( 0 << 15)
366	#define FLAG_RESPONSE ( 1 << 15)	393	#define FLAG_RESPONSE ( 1 << 15)
367	#define FLAG_OP_MASK (15 << 14)	394	#define FLAG_OP_MASK (15 << 11)
368	#define FLAG_OP_QUERY ( 0 << 11)	395	#define FLAG_OP_QUERY ( 0 << 11)
369	#define FLAG_AA ( 1 << 10)	396	#define FLAG_AA ( 1 << 10)
370	#define FLAG_TC ( 1 << 9)	397	#define FLAG_TC ( 1 << 9)
371	#define FLAG_RD ( 1 << 8)	398	#define FLAG_RD ( 1 << 8)
372	#define FLAG_RA ( 1 << 7)	399	#define FLAG_RA ( 1 << 7)
…		…
379	#define FLAG_RCODE_REFUSED ( 5 << 0)	406	#define FLAG_RCODE_REFUSED ( 5 << 0)
380		407
381	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)	408	#define DEFAULT_CLIENT_FLAGS (FLAG_QUERY \| FLAG_OP_QUERY \| FLAG_RD)
382	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)	409	#define DEFAULT_SERVER_FLAGS (FLAG_RESPONSE \| FLAG_OP_QUERY \| FLAG_AA \| FLAG_RD \| FLAG_RA)
383		410
		411	struct dns_cfg
		412	{
		413	static int next_uid;
		414
		415	u8 id1, id2, id3, id4;
		416
		417	u8 version;
		418	u8 flags;
		419	u8 rrtype;
		420	u8 def_ttl;
		421
		422	u16 client;
		423	u16 uid; // to make request unique
		424
		425	u16 max_size;
		426	u8 seq_cdc;
		427	u8 req_cdc;
		428
		429	u8 rep_cdc;
		430	u8 delay; // time in 0.01s units that the server may delay replying packets
		431	u8 r3, r4;
		432
		433	u8 r5, r6, r7, r8;
		434
		435	void reset (int clientid);
		436	bool valid ();
		437	};
		438
		439	int dns_cfg::next_uid;
		440
		441	void dns_cfg::reset (int clientid)
		442	{
		443	id1 = 'G';
		444	id2 = 'V';
		445	id3 = 'P';
		446	id4 = 'E';
		447
		448	version = 1;
		449
		450	rrtype = RR_TYPE_TXT;
		451	flags = 0;
		452	def_ttl = 0;
		453	seq_cdc = 26;
		454	req_cdc = 62;
		455	rep_cdc = 0;
		456	max_size = htons (MAX_PKT_SIZE);
		457	client = htons (clientid);
		458	uid = next_uid++;
		459	delay = 0;
		460
		461	r3 = r4 = 0;
		462	r4 = r5 = r6 = r7 = 0;
		463	}
		464
		465	bool dns_cfg::valid ()
		466	{
		467	return id1 == 'G'
		468	&& id2 == 'V'
		469	&& id3 == 'P'
		470	&& id4 == 'E'
		471	&& seq_cdc == 26
		472	&& req_cdc == 62
		473	&& rep_cdc == 0
		474	&& version == 1;
		475	}
		476
384	struct dns_packet : net_packet	477	struct dns_packet : net_packet
385	{	478	{
386	u16 id;	479	u16 id;
387	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4	480	u16 flags; // QR:1 Opcode:4 AA:1 TC:1 RD:1 RA:1 Z:3 RCODE:4
388	u16 qdcount, ancount, nscount, arcount;	481	u16 qdcount, ancount, nscount, arcount;
389		482
390	u8 data[MAXSIZE - 6 * 2];	483	u8 data [MAXSIZE - 6 * 2];
391		484
392	int decode_label (char *data, int size, int &offs);	485	int decode_label (char *data, int size, int &offs);
393	};	486	};
394		487
395	int dns_packet::decode_label (char *data, int size, int &offs)	488	int dns_packet::decode_label (char *data, int size, int &offs)
…		…
426	return data - orig;	519	return data - orig;
427	}	520	}
428		521
429	/////////////////////////////////////////////////////////////////////////////	522	/////////////////////////////////////////////////////////////////////////////
430		523
431	struct dns_req
432	{
433	dns_packet *pkt;
434	tstamp next;
435	int retry;
436	connection *conn;
437	int seqno;
438
439	dns_req (connection *c);
440	void gen_stream_req (int seqno, byte_stream *stream);
441	};
442
443	static u16 dns_id = 12098; // TODO: should be per-vpn	524	static u16 dns_id = 0; // TODO: should be per-vpn
444		525
445	static u16 next_id ()	526	static u16 next_id ()
446	{	527	{
		528	if (!dns_id)
		529	dns_id = time (0);
		530
447	// the simplest lsfr with periodicity 65535 i could find	531	// the simplest lsfr with periodicity 65535 i could find
448	dns_id = (dns_id << 1)	532	dns_id = (dns_id << 1)
449	\| (((dns_id >> 1)	533	\| (((dns_id >> 1)
450	^ (dns_id >> 2)	534	^ (dns_id >> 2)
451	^ (dns_id >> 4)	535	^ (dns_id >> 4)
452	^ (dns_id >> 15)) & 1);	536	^ (dns_id >> 15)) & 1);
453		537
454	return dns_id;	538	return dns_id;
455	}	539	}
456		540
457	dns_req::dns_req (connection *c)	541	struct dns_rcv;
458	: conn (c)	542	struct dns_snd;
		543
		544	struct dns_connection
459	{	545	{
460	next = 0;	546	connection *c;
		547	struct vpn *vpn;
		548
		549	dns_cfg cfg;
		550
		551	bool established;
		552
		553	tstamp last_received;
		554	tstamp last_sent;
		555	double min_latency;
		556	double poll_interval, send_interval;
		557
		558	vector<dns_rcv *> rcvpq;
		559
		560	byte_stream rcvdq; int rcvseq; int repseq;
		561	byte_stream snddq; int sndseq;
		562
		563	void time_cb (time_watcher &w); time_watcher tw;
		564	void receive_rep (dns_rcv *r);
		565
		566	dns_connection (connection *c);
		567	~dns_connection ();
		568	};
		569
		570	struct dns_snd
		571	{
		572	dns_packet *pkt;
		573	tstamp timeout, sent;
		574	int retry;
		575	struct dns_connection *dns;
		576	int seqno;
		577	bool stdhdr;
		578
		579	void gen_stream_req (int seqno, byte_stream &stream);
		580	void gen_syn_req ();
		581
		582	dns_snd (dns_connection *dns);
		583	~dns_snd ();
		584	};
		585
		586	dns_snd::dns_snd (dns_connection *dns)
		587	: dns (dns)
		588	{
		589	timeout = 0;
461	retry = 0;	590	retry = 0;
		591	seqno = 0;
		592	sent = NOW;
		593	stdhdr = false;
462		594
463	pkt = new dns_packet;	595	pkt = new dns_packet;
464		596
465	pkt->id = next_id ();	597	pkt->id = next_id ();
466	}	598	}
467		599
		600	dns_snd::~dns_snd ()
		601	{
		602	delete pkt;
		603	}
		604
		605	static void append_domain (dns_packet &pkt, int &offs, const char *domain)
		606	{
		607	// add tunnel domain
		608	for (;;)
		609	{
		610	const char *end = strchr (domain, '.');
		611
		612	if (!end)
		613	end = domain + strlen (domain);
		614
		615	int len = end - domain;
		616
		617	pkt [offs++] = len;
		618	memcpy (pkt.at (offs), domain, len);
		619	offs += len;
		620
		621	if (!*end)
		622	break;
		623
		624	domain = end + 1;
		625	}
		626	}
		627
468	void dns_req::gen_stream_req (int seqno, byte_stream *stream)	628	void dns_snd::gen_stream_req (int seqno, byte_stream &stream)
469	{	629	{
		630	stdhdr = true;
470	this->seqno = seqno;	631	this->seqno = seqno;
		632
		633	timeout = NOW + INITIAL_TIMEOUT;
471		634
472	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);	635	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
473	pkt->qdcount = htons (1);	636	pkt->qdcount = htons (1);
474		637
475	int offs = 6*2;	638	int offs = 6*2;
476	int dlen = MAX_DOMAIN_SIZE - (strlen (THISNODE->domain) + 2);	639	int dlen = MAX_DOMAIN_SIZE - (strlen (dns->c->conf->domain) + 2);
477	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,	640	// MAX_DOMAIN_SIZE is technically 255, but bind doesn't compress responses well,
478	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra	641	// so we need to have space for 2*MAX_DOMAIN_SIZE + header + extra
479		642
480	char enc[256], *encp = enc;	643	char enc[256], *encp = enc;
481	encode_header (enc, THISNODE->id, seqno);	644	encode_header (enc, THISNODE->id, seqno);
482		645
483	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);	646	int datalen = cdc62.decode_len (dlen - (dlen + MAX_LBL_SIZE - 1) / MAX_LBL_SIZE - HDRSIZE);
484		647
485	if (datalen > stream->size ())	648	if (datalen > stream.size ())
486	datalen = stream->size ();	649	datalen = stream.size ();
487		650
488	int enclen = cdc62.encode (enc + HDRSIZE, stream->begin (), datalen) + HDRSIZE;	651	int enclen = cdc62.encode (enc + HDRSIZE, stream.begin (), datalen) + HDRSIZE;
489
490	printf ("cdc62.encode %d->%d:%02x %02x %02x %02x\n", datalen, enclen,
491	stream->begin ()[0],
492	stream->begin ()[1],
493	stream->begin ()[2],
494	stream->begin ()[3]);
495
496	stream->remove (datalen);	652	stream.remove (datalen);
497		653
498	while (enclen)	654	while (enclen)
499	{	655	{
500	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;	656	int lbllen = enclen < MAX_LBL_SIZE ? enclen : MAX_LBL_SIZE;
501		657
…		…
506	encp += lbllen;	662	encp += lbllen;
507		663
508	enclen -= lbllen;	664	enclen -= lbllen;
509	}	665	}
510		666
511	const char *suffix = THISNODE->domain;	667	append_domain (*pkt, offs, dns->c->conf->domain);
512
513	// add tunnel domain
514	for (;;)
515	{
516	const char *end = strchr (suffix, '.');
517
518	if (!end)
519	end = suffix + strlen (suffix);
520
521	int len = end - suffix;
522
523	(*pkt)[offs++] = len;
524	memcpy (&((*pkt)[offs]), suffix, len);
525	offs += len;
526
527	if (!*end)
528	break;
529
530	suffix = end + 1;
531	}
532		668
533	(*pkt)[offs++] = 0;	669	(*pkt)[offs++] = 0;
534	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;	670	(pkt)[offs++] = RR_TYPE_ANY >> 8; (pkt)[offs++] = RR_TYPE_ANY;
		671	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
		672
		673	pkt->len = offs;
		674	}
		675
		676	void dns_snd::gen_syn_req ()
		677	{
		678	timeout = NOW + INITIAL_SYN_TIMEOUT;
		679
		680	pkt->flags = htons (DEFAULT_CLIENT_FLAGS);
		681	pkt->qdcount = htons (1);
		682
		683	int offs = 6 * 2;
		684
		685	int elen = cdc26.encode ((char )pkt->at (offs + 1), (u8 )&dns->cfg, sizeof (dns_cfg));
		686
		687	assert (elen <= MAX_LBL_SIZE);
		688
		689	(*pkt)[offs] = elen;
		690	offs += elen + 1;
		691	append_domain (*pkt, offs, dns->c->conf->domain);
		692
		693	(*pkt)[offs++] = 0;
		694	(pkt)[offs++] = RR_TYPE_A >> 8; (pkt)[offs++] = RR_TYPE_A;
535	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;	695	(pkt)[offs++] = RR_CLASS_IN >> 8; (pkt)[offs++] = RR_CLASS_IN;
536		696
537	pkt->len = offs;	697	pkt->len = offs;
538	}	698	}
539		699
…		…
558	{	718	{
559	delete pkt;	719	delete pkt;
560	}	720	}
561		721
562	/////////////////////////////////////////////////////////////////////////////	722	/////////////////////////////////////////////////////////////////////////////
563		723
564	struct dns_cfg	724	dns_connection::dns_connection (connection *c)
		725	: c (c)
		726	, rcvdq (MAX_BACKLOG * 2)
		727	, snddq (MAX_BACKLOG)
		728	, tw (this, &dns_connection::time_cb)
565	{	729	{
566	u8 id1, id2, id3;	730	vpn = c->vpn;
567	u8 def_ttl;
568	u8 unused1;
569	u16 max_size;
570	u8 flags1, flags2;
571	};
572		731
		732	established = false;
		733
		734	rcvseq = repseq = sndseq = 0;
		735
		736	last_sent = last_received = 0;
		737	poll_interval = 0.5; // starting here
		738	send_interval = 0.5; // starting rate
		739	min_latency = INITIAL_TIMEOUT;
		740	}
		741
		742	dns_connection::~dns_connection ()
		743	{
		744	for (vector<dns_rcv *>::iterator i = rcvpq.begin ();
		745	i != rcvpq.end ();
		746	++i)
		747	delete *i;
		748	}
		749
573	void connection::dnsv4_receive_rep (struct dns_rcv *r)	750	void dns_connection::receive_rep (dns_rcv *r)
574	{	751	{
		752	if (r->datalen)
		753	{
		754	last_received = NOW;
		755	tw.trigger ();
		756
		757	poll_interval = send_interval;
		758	}
		759	else
		760	{
		761	poll_interval *= 1.5;
		762
		763	if (poll_interval > MAX_POLL_INTERVAL)
		764	poll_interval = MAX_POLL_INTERVAL;
		765	}
		766
575	dns_rcvpq.push_back (r);	767	rcvpq.push_back (r);
576		768
577	printf ("%d got inketc %d (%02x %02x %02x %02x)\n", THISNODE->id, r->seqno
578	,r->data[0]
579	,r->data[1]
580	,r->data[2]
581	,r->data[3]
582	);
583	redo:	769	redo:
584		770
585	// find next packet	771	// find next packet
586	for (vector<dns_rcv *>::iterator i = dns_rcvpq.end (); i-- != dns_rcvpq.begin (); )	772	for (vector<dns_rcv *>::iterator i = rcvpq.end (); i-- != rcvpq.begin (); )
587	if (SEQNO_EQ (dns_rcvseq, (*i)->seqno))	773	if (SEQNO_EQ (rcvseq, (*i)->seqno))
588	{	774	{
589	// enter the packet into our input stream	775	// enter the packet into our input stream
590	r = *i;	776	r = *i;
591		777
592	printf ("%d checking for older packet %d\n", THISNODE->id, dns_rcvseq);
593	// remove the oldest packet, look forward, as it's oldest first	778	// remove the oldest packet, look forward, as it's oldest first
594	for (vector<dns_rcv *>::iterator j = dns_rcvpq.begin (); j != dns_rcvpq.end (); ++j)	779	for (vector<dns_rcv *>::iterator j = rcvpq.begin (); j != rcvpq.end (); ++j)
595	if (SEQNO_EQ ((*j)->seqno, dns_rcvseq - MAX_WINDOW))	780	if (SEQNO_EQ ((*j)->seqno, rcvseq - MAX_WINDOW))
596	{	781	{
597	printf ("%d removing %d\n", THISNODE->id, (*j)->seqno);
598	delete *j;	782	delete *j;
599	dns_rcvpq.erase (j);	783	rcvpq.erase (j);
600	break;	784	break;
601	}	785	}
602		786
603	dns_rcvseq = (dns_rcvseq + 1) & SEQNO_MASK;	787	rcvseq = (rcvseq + 1) & SEQNO_MASK;
604		788
605	if (!dns_snddq && !dns_rcvdq)	789	if (!rcvdq.put (r->data, r->datalen))
606	{	790	{
607	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);	791	slog (L_ERR, "DNS: !rcvdq.put (r->data, r->datalen)");
608	dns_snddq = new byte_stream (MAX_BACKLOG);	792	abort (); // MUST never overflow, can be caused by data corruption, TODO
609
610	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);
611	}	793	}
612		794
613	if (!dns_rcvdq->put (r->data, r->datalen))
614	abort (); // MUST never overflow, can be caused by data corruption, TODO
615
616	while (vpn_packet *pkt = dns_rcvdq->get ())	795	while (vpn_packet *pkt = rcvdq.get ())
617	{	796	{
618	sockinfo si;	797	sockinfo si;
619	si.host = 0; si.port = 0; si.prot = PROT_DNSv4;	798	si.host = htonl (c->conf->id); si.port = 0; si.prot = PROT_DNSv4;
620		799
621	vpn->recv_vpn_packet (pkt, si);	800	vpn->recv_vpn_packet (pkt, si);
		801
		802	delete pkt;
622	}	803	}
623		804
624	// check for further packets	805	// check for further packets
625	goto redo;	806	goto redo;
626	}	807	}
627	}	808	}
628		809
629	dns_packet *	810	void
630	vpn::dnsv4_server (dns_packet *pkt)	811	vpn::dnsv4_server (dns_packet &pkt)
631	{	812	{
632	u16 flags = ntohs (pkt->flags);	813	u16 flags = ntohs (pkt.flags);
633		814
634	//memcpy (&((rep)[0]), &((pkt)[0]), pkt->len);
635	int offs = 6 * 2; // skip header	815	int offs = 6 * 2; // skip header
636		816
637	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);	817	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
638		818
639	if (!(flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	819	if (0 == (flags & (FLAG_RESPONSE \| FLAG_OP_MASK))
640	&& pkt->qdcount == htons (1))	820	&& pkt.qdcount == htons (1))
641	{	821	{
642	char qname[MAXSIZE];	822	char qname [MAXSIZE];
643	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	823	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
644		824
645	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	825	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
646	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	826	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
647		827
648	pkt->qdcount = htons (1);	828	pkt.qdcount = htons (1);
649	pkt->ancount = 0;	829	pkt.ancount = 0;
650	pkt->nscount = 0; // should be self, as other nameservers reply like this	830	pkt.nscount = 0; // should be self, as other nameservers reply like this
651	pkt->arcount = 0; // a record for self, as other nameservers reply like this	831	pkt.arcount = 0; // a record for self, as other nameservers reply like this
652		832
653	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_NXDOMAIN);	833	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_SERVFAIL);
654		834
655	int dlen = strlen (THISNODE->domain);	835	int dlen = strlen (THISNODE->domain);
656		836
657	if (qclass == RR_CLASS_IN	837	if (qclass == RR_CLASS_IN
658	&& (qtype == RR_TYPE_ANY \|\| qtype == RR_TYPE_TXT)
659	&& qlen > dlen + 1 + HDRSIZE	838	&& qlen > dlen + 1
660	&& !memcmp (qname + qlen - dlen - 1, THISNODE->domain, dlen))	839	&& !memcmp (qname + qlen - (dlen + 1), THISNODE->domain, dlen))
661	{	840	{
662	// correct class, domain: parse	841	// now generate reply
663	int client, seqno;	842	pkt.ancount = htons (1); // one answer RR
664	decode_header (qname, client, seqno);	843	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);
665		844
666	u8 data[MAXSIZE];	845	if ((qtype == RR_TYPE_ANY
667	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));	846	\|\| qtype == RR_TYPE_TXT
668		847	\|\| qtype == RR_TYPE_NULL)
669	printf ("cdc62.decode %d(%d): %02x %02x %02x %02x\n",
670	qlen - (dlen + 1 + HDRSIZE), datalen	848	&& qlen > dlen + 1 + HDRSIZE)
671	,data[0]
672	,data[1]
673	,data[2]
674	,data[3]);
675
676	printf ("SRV got %d <%.*s>\n", seqno, qlen, qname + HDRSIZE);//D
677	printf ("SRV got %d <%.*s>\n", seqno, qlen - (dlen + 1 + HDRSIZE), qname + HDRSIZE);//D
678
679	if (0 < client && client <= conns.size ())
680	{	849	{
		850	// correct class, domain: parse
		851	int client, seqno;
		852	decode_header (qname, client, seqno);
		853
		854	u8 data[MAXSIZE];
		855	int datalen = cdc62.decode (data, qname + HDRSIZE, qlen - (dlen + 1 + HDRSIZE));
		856
		857	if (0 < client && client <= conns.size ())
		858	{
681	connection *c = conns [client - 1];	859	connection *c = conns [client - 1];
		860	dns_connection *dns = c->dns;
		861	dns_rcv *rcv;
682		862
		863	if (dns)
		864	{
683	for (vector<dns_rcv *>::iterator i = c->dns_rcvpq.end (); i-- != c->dns_rcvpq.begin (); )	865	for (vector<dns_rcv *>::iterator i = dns->rcvpq.end (); i-- != dns->rcvpq.begin (); )
684	if (SEQNO_EQ ((*i)->seqno, seqno))	866	if (SEQNO_EQ ((*i)->seqno, seqno))
		867	{
		868	// already seen that request: simply reply with the cached reply
		869	dns_rcv r = i;
		870
		871	slog (L_DEBUG, "DNS: duplicate packet received ID %d, SEQ %d", htons (r->pkt->id), seqno);
		872
		873	// refresh header & id, as the retry count could have changed
		874	memcpy (r->pkt->at (6 * 2 + 1), pkt.at (6 * 2 + 1), HDRSIZE);
		875	r->pkt->id = pkt.id;
		876
		877	memcpy (pkt.at (0), r->pkt->at (0), offs = r->pkt->len);
		878
		879	goto duplicate_request;
		880	}
		881
		882	// new packet, queue
		883	rcv = new dns_rcv (seqno, data, datalen);
		884	dns->receive_rep (rcv);
		885	}
		886
685	{	887	{
686	// already seen that request: simply reply with the cached reply	888	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
687	dns_rcv r = i;
688		889
689	printf ("DUPLICATE %d\n", htons (r->pkt->id));//D	890	int rtype = dns ? dns->cfg.rrtype : RR_TYPE_A;
		891	pkt [offs++] = rtype >> 8; pkt [offs++] = rtype; // type
		892	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
		893	pkt [offs++] = 0; pkt [offs++] = 0;
		894	pkt [offs++] = 0; pkt [offs++] = dns ? dns->cfg.def_ttl : 0; // TTL
690		895
691	memcpy (pkt->at (0), r->pkt->at (0), offs = r->pkt->len);	896	int rdlen_offs = offs += 2;
692	pkt->id = r->pkt->id;	897
693	goto duplicate_request;	898	if (dns)
		899	{
		900	int dlen = ntohs (dns->cfg.max_size) - offs;
		901
		902	// bind doesn't compress well, so reduce further by one label length
		903	dlen -= qlen;
		904
		905	// only put data into in-order sequence packets, if
		906	// we receive out-of-order packets we generate empty
		907	// replies
		908	//printf ("%d - %d & %x (=%d) < %d\n", seqno, dns->repseq, SEQNO_MASK, (seqno - dns->repseq) & SEQNO_MASK, MAX_WINDOW);//D
		909	if (((seqno - dns->repseq) & SEQNO_MASK) <= MAX_WINDOW)
		910	{
		911	dns->repseq = seqno;
		912
		913	while (dlen > 1 && !dns->snddq.empty ())
		914	{
		915	int txtlen = dlen <= 255 ? dlen - 1 : 255;
		916
		917	if (txtlen > dns->snddq.size ())
		918	txtlen = dns->snddq.size ();
		919
		920	pkt[offs++] = txtlen;
		921	memcpy (pkt.at (offs), dns->snddq.begin (), txtlen);
		922	offs += txtlen;
		923	dns->snddq.remove (txtlen);
		924
		925	dlen -= txtlen + 1;
		926	}
		927	}
		928
		929	// avoid completely empty TXT rdata
		930	if (offs == rdlen_offs)
		931	pkt[offs++] = 0;
		932
		933	slog (L_NOISE, "DNS: snddq %d", dns->snddq.size ());
		934	}
		935	else
		936	{
		937	// send RST
		938	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
		939	pkt [offs++] = CMD_IP_RST;
		940	}
		941
		942	int rdlen = offs - rdlen_offs;
		943
		944	pkt [rdlen_offs - 2] = rdlen >> 8;
		945	pkt [rdlen_offs - 1] = rdlen;
		946
		947	if (dns)
		948	{
		949	// now update dns_rcv copy
		950	rcv->pkt->len = offs;
		951	memcpy (rcv->pkt->at (0), pkt.at (0), offs);
		952	}
694	}	953	}
695		954
696	// new packet, queue	955	duplicate_request: ;
697	dns_rcv *rcv = new dns_rcv (seqno, data, datalen);	956	}
698	c->dnsv4_receive_rep (rcv);	957	else
699
700	// now generate reply
701	pkt->ancount = htons (1); // one answer RR
702	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_OK);	958	pkt.flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
		959	}
		960	else if (qtype == RR_TYPE_A
		961	&& qlen > dlen + 1 + cdc26.encode_len (sizeof (dns_cfg)))
		962	{
		963	dns_cfg cfg;
		964	cdc26.decode ((u8 *)&cfg, qname, cdc26.encode_len (sizeof (dns_cfg)));
		965	int client = ntohs (cfg.client);
703		966
704	(*pkt) [offs++] = 0xc0;
705	(pkt) [offs++] = 6 2; // same as in query section	967	pkt [offs++] = 0xc0; pkt [offs++] = 6 * 2; // refer to name in query section
706		968
707	(pkt) [offs++] = RR_TYPE_TXT >> 8; (pkt) [offs++] = RR_TYPE_TXT;	969	pkt [offs++] = RR_TYPE_A >> 8; pkt [offs++] = RR_TYPE_A; // type
708	(pkt) [offs++] = RR_CLASS_IN >> 8; (pkt) [offs++] = RR_CLASS_IN;	970	pkt [offs++] = RR_CLASS_IN >> 8; pkt [offs++] = RR_CLASS_IN; // class
709
710	(pkt) [offs++] = 0; (pkt) [offs++] = 0;	971	pkt [offs++] = 0; pkt [offs++] = 0;
711	(pkt) [offs++] = 0; (pkt) [offs++] = 0; // TTL	972	pkt [offs++] = 0; pkt [offs++] = cfg.def_ttl; // TTL
		973	pkt [offs++] = 0; pkt [offs++] = 4; // rdlength
712		974
713	int dlen = MAX_PKT_SIZE - offs - 2;	975	slog (L_INFO, _("DNS: client %d connects"), client);
714		976
715	// bind doesn't compress well, so reduce further by one label length	977	pkt [offs++] = CMD_IP_1; pkt [offs++] = CMD_IP_2; pkt [offs++] = CMD_IP_3;
716	dlen -= qlen;	978	pkt [offs++] = CMD_IP_REJ;
717		979
718	int rdlen_offs = offs += 2;	980	if (0 < client && client <= conns.size ())
719
720	while (c->dns_snddq
721	&& !c->dns_snddq->empty ()
722	&& dlen > 1)
723	{	981	{
724	int txtlen = dlen <= 255 ? dlen - 1 : 255;	982	connection *c = conns [client - 1];
725		983
726	if (txtlen > c->dns_snddq->size ())	984	if (cfg.valid ())
727	txtlen = c->dns_snddq->size ();	985	{
		986	pkt [offs - 1] = CMD_IP_SYN;
728		987
729	(*pkt)[offs++] = txtlen;	988	delete c->dns;
730	memcpy (pkt->at (offs), c->dns_snddq->begin (), txtlen);	989	c->dns = new dns_connection (c);
731	offs += txtlen;	990	c->dns->cfg = cfg;
732	c->dns_snddq->remove (txtlen);	991	}
733
734	dlen -= txtlen + 1;
735	}	992	}
736
737	// avoid empty TXT rdata
738	if (offs == rdlen_offs)
739	(*pkt)[offs++] = 0;
740
741	int rdlen = offs - rdlen_offs;
742
743	(*pkt) [rdlen_offs - 2] = rdlen >> 8;
744	(*pkt) [rdlen_offs - 1] = rdlen;
745
746	// now update dns_rcv copy
747	rcv->pkt->len = offs;
748	memcpy (rcv->pkt->at (0), pkt->at (0), offs);
749
750	duplicate_request: ;
751	}	993	}
752	else
753	pkt->flags = htons (DEFAULT_SERVER_FLAGS \| FLAG_RCODE_FORMERR);
754	}	994	}
755		995
756	pkt->len = offs;	996	pkt.len = offs;
757	}	997	}
758
759	return pkt;
760	}	998	}
761		999
762	void	1000	void
763	vpn::dnsv4_client (dns_packet *pkt)	1001	vpn::dnsv4_client (dns_packet &pkt)
764	{	1002	{
765	u16 flags = ntohs (pkt->flags);	1003	u16 flags = ntohs (pkt.flags);
766	int offs = 6 * 2; // skip header	1004	int offs = 6 * 2; // skip header
767		1005
768	pkt->qdcount = ntohs (pkt->qdcount);	1006	pkt.qdcount = ntohs (pkt.qdcount);
769	pkt->ancount = ntohs (pkt->ancount);	1007	pkt.ancount = ntohs (pkt.ancount);
770		1008
771	// go through our request list and find the corresponding request	1009	// go through our request list and find the corresponding request
772	for (vector<dns_req *>::iterator i = dns_sndpq.begin ();	1010	for (vector<dns_snd *>::iterator i = dns_sndpq.begin ();
773	i != dns_sndpq.end ();	1011	i != dns_sndpq.end ();
774	++i)	1012	++i)
775	if ((*i)->pkt->id == pkt->id)	1013	if ((*i)->pkt->id == pkt.id)
776	{	1014	{
		1015	dns_connection dns = (i)->dns;
777	connection c = (i)->conn;	1016	connection *c = dns->c;
778	int seqno = (*i)->seqno;	1017	int seqno = (*i)->seqno;
779	u8 data[MAXSIZE], *datap = data;	1018	u8 data[MAXSIZE], *datap = data;
780		1019
		1020	if ((*i)->retry)
		1021	{
		1022	dns->send_interval *= 1.01;
		1023	if (dns->send_interval > MAX_SEND_INTERVAL)
		1024	dns->send_interval = MAX_SEND_INTERVAL;
		1025	}
		1026	else
		1027	{
		1028	#if 0
		1029	dns->send_interval *= 0.999;
		1030	#endif
		1031	// the latency surely puts an upper bound on
		1032	// the minimum send interval
		1033	double latency = NOW - (*i)->sent;
		1034
		1035	if (latency < dns->min_latency)
		1036	dns->min_latency = latency;
		1037
		1038	if (dns->send_interval > dns->min_latency * LATENCY_FACTOR)
		1039	dns->send_interval = dns->min_latency * LATENCY_FACTOR;
		1040
		1041	if (dns->send_interval < MIN_SEND_INTERVAL)
		1042	dns->send_interval = MIN_SEND_INTERVAL;
		1043	}
		1044
781	delete *i;	1045	delete *i;
782	dns_sndpq.erase (i);	1046	dns_sndpq.erase (i);
783		1047
784	if (flags & (FLAG_RESPONSE \| FLAG_OP_MASK \| FLAG_TC))	1048	if (flags & FLAG_RESPONSE && !(flags & FLAG_OP_MASK))
785	{	1049	{
786	char qname[MAXSIZE];	1050	char qname[MAXSIZE];
787		1051
788	while (pkt->qdcount-- && offs < MAXSIZE - 4)	1052	while (pkt.qdcount-- && offs < MAXSIZE - 4)
789	{	1053	{
790	int qlen = pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1054	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
791	offs += 4; // skip qtype, qclass	1055	offs += 4; // skip qtype, qclass
792	}	1056	}
793		1057
794	while (pkt->ancount-- && offs < MAXSIZE - 10)	1058	while (pkt.ancount-- && offs < MAXSIZE - 10 && datap)
795	{	1059	{
796	int qlen = //D
797	pkt->decode_label ((char *)qname, MAXSIZE - offs, offs);	1060	int qlen = pkt.decode_label ((char *)qname, MAXSIZE - offs, offs);
798		1061
799	printf ("got reply to <%.*s>\n", qlen, qname);//D
800
801	u16 qtype = (pkt) [offs++] << 8; qtype \|= (pkt) [offs++];	1062	u16 qtype = pkt [offs++] << 8; qtype \|= pkt [offs++];
802	u16 qclass = (pkt) [offs++] << 8; qclass \|= (pkt) [offs++];	1063	u16 qclass = pkt [offs++] << 8; qclass \|= pkt [offs++];
803	u32 ttl = (*pkt) [offs++] << 24;	1064	u32 ttl = pkt [offs++] << 24;
804	ttl \|= (*pkt) [offs++] << 16;	1065	ttl \|= pkt [offs++] << 16;
805	ttl \|= (*pkt) [offs++] << 8;	1066	ttl \|= pkt [offs++] << 8;
806	ttl \|= (*pkt) [offs++];	1067	ttl \|= pkt [offs++];
807
808	u16 rdlen = (pkt) [offs++] << 8; rdlen \|= (pkt) [offs++];	1068	u16 rdlen = pkt [offs++] << 8; rdlen \|= pkt [offs++];
809		1069
810	if (rdlen <= MAXSIZE - offs)	1070	if (qtype == RR_TYPE_NULL \|\| qtype == RR_TYPE_TXT)
811	{	1071	{
812	// decode bytes, finally	1072	if (rdlen <= MAXSIZE - offs)
813
814	while (rdlen)
815	{	1073	{
		1074	// decode bytes, finally
		1075
		1076	while (rdlen)
		1077	{
816	int txtlen = (*pkt) [offs++];	1078	int txtlen = pkt [offs++];
817		1079
818	assert (txtlen + offs < MAXSIZE - 1);	1080	assert (txtlen + offs < MAXSIZE - 1);
819		1081
820	memcpy (datap, pkt->at (offs), txtlen);	1082	memcpy (datap, pkt.at (offs), txtlen);
821	datap += txtlen; offs += txtlen;	1083	datap += txtlen; offs += txtlen;
822		1084
823	rdlen -= txtlen + 1;	1085	rdlen -= txtlen + 1;
		1086	}
824	}	1087	}
825
826	}	1088	}
		1089	else if (qtype == RR_TYPE_A)
		1090	{
		1091	u8 ip [4];
827		1092
		1093	ip [0] = pkt [offs++];
		1094	ip [1] = pkt [offs++];
		1095	ip [2] = pkt [offs++];
		1096	ip [3] = pkt [offs++];
		1097
		1098	if (ip [0] == CMD_IP_1
		1099	&& ip [1] == CMD_IP_2
		1100	&& ip [2] == CMD_IP_3)
		1101	{
		1102	slog (L_TRACE, _("DNS: got tunnel meta command %02x"), ip [3]);
		1103
		1104	if (ip [3] == CMD_IP_RST)
		1105	{
		1106	slog (L_DEBUG, _("DNS: got tunnel RST request"));
		1107
		1108	delete dns; c->dns = 0;
		1109
		1110	return;
		1111	}
		1112	else if (ip [3] == CMD_IP_SYN)
		1113	{
		1114	slog (L_DEBUG, _("DNS: got tunnel SYN reply, server likes us."));
		1115	dns->established = true;
		1116	}
		1117	else if (ip [3] == CMD_IP_REJ)
		1118	{
		1119	slog (L_DEBUG, _("DNS: got tunnel REJ reply, server does not like us, aborting."));
		1120	abort ();
		1121	}
		1122	else
		1123	slog (L_INFO, _("DNS: got unknown meta command %02x"), ip [3]);
		1124	}
		1125	else
		1126	slog (L_INFO, _("DNS: got spurious a record %d.%d.%d.%d"),
		1127	ip [0], ip [1], ip [2], ip [3]);
		1128
		1129	return;
		1130	}
		1131
		1132	int client, rseqno;
		1133	decode_header (qname, client, rseqno);
		1134
		1135	if (client != THISNODE->id)
		1136	{
		1137	slog (L_INFO, _("DNS: got dns tunnel response with wrong clientid, ignoring"));
		1138	datap = 0;
		1139	}
		1140	else if (rseqno != seqno)
		1141	{
		1142	slog (L_DEBUG, _("DNS: got dns tunnel response with wrong seqno, badly caching nameserver?"));
		1143	datap = 0;
		1144	}
828	}	1145	}
829	}	1146	}
830		1147
831	// todo: pkt now used	1148	// todo: pkt now used
		1149	if (datap)
832	c->dnsv4_receive_rep (new dns_rcv (seqno, data, datap - data));	1150	dns->receive_rep (new dns_rcv (seqno, data, datap - data));
833		1151
834	break;	1152	break;
835	}	1153	}
836
837	delete pkt;
838	}	1154	}
839		1155
840	void	1156	void
841	vpn::dnsv4_ev (io_watcher &w, short revents)	1157	vpn::dnsv4_ev (io_watcher &w, short revents)
842	{	1158	{
…		…
844	{	1160	{
845	dns_packet *pkt = new dns_packet;	1161	dns_packet *pkt = new dns_packet;
846	struct sockaddr_in sa;	1162	struct sockaddr_in sa;
847	socklen_t sa_len = sizeof (sa);	1163	socklen_t sa_len = sizeof (sa);
848		1164
849	pkt->len = recvfrom (w.fd, &((pkt)[0]), MAXSIZE, 0, (sockaddr )&sa, &sa_len);	1165	pkt->len = recvfrom (w.fd, pkt->at (0), MAXSIZE, 0, (sockaddr *)&sa, &sa_len);
850		1166
851	if (pkt->len > 0)	1167	if (pkt->len > 0)
852	{	1168	{
853	if (pkt->flags & htons (FLAG_TC))	1169	if (ntohs (pkt->flags) & FLAG_RESPONSE)
		1170	dnsv4_client (*pkt);
		1171	else
854	{	1172	{
855	slog (L_WARN, _("DNS request/response truncated, check protocol settings."));	1173	dnsv4_server (*pkt);
856	//TODO connection reset	1174	sendto (w.fd, pkt->at (0), pkt->len, 0, (sockaddr *)&sa, sa_len);
857	}	1175	}
858		1176
859	if (THISNODE->dns_port)	1177	delete pkt;
860	{
861	pkt = dnsv4_server (pkt);
862	sendto (w.fd, &((pkt)[0]), pkt->len, 0, (sockaddr )&sa, sa_len);
863	}
864	else
865	dnsv4_client (pkt);
866	}	1178	}
867	}	1179	}
868	}	1180	}
869		1181
870	bool	1182	bool
871	connection::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)	1183	vpn::send_dnsv4_packet (vpn_packet *pkt, const sockinfo &si, int tos)
872	{	1184	{
873	// never initialized	1185	int client = ntohl (si.host);
874	if (!dns_snddq && !dns_rcvdq)
875	{
876	dns_rcvdq = new byte_stream (MAX_BACKLOG * 2);
877	dns_snddq = new byte_stream (MAX_BACKLOG);
878		1186
879	//dns_rcvseq = dns_sndseq = 0;	1187	assert (0 < client && client <= conns.size ());
880		1188
881	dns_si.set (::conf.dns_forw_host, ::conf.dns_forw_port, PROT_DNSv4);	1189	connection *c = conns [client - 1];
882	}	1190
		1191	if (!c->dns)
		1192	c->dns = new dns_connection (c);
883		1193
884	if (!dns_snddq->put (pkt))	1194	if (c->dns->snddq.put (pkt))
885	return false;	1195	c->dns->tw.trigger ();
886		1196
887	// start timer if neccessary	1197	// always return true even if the buffer overflows
888	if (!THISNODE->dns_port && !dnsv4_tw.active)
889	dnsv4_cb (dnsv4_tw);
890
891	return true;	1198	return true;
892	}	1199	}
893		1200
894	void	1201	void
		1202	connection::dnsv4_reset_connection ()
		1203	{
		1204	//delete dns; dns = 0; //TODO
		1205	}
		1206
		1207	#define NEXT(w) do { if (next > (w)) next = w; } while (0)
		1208
		1209	void
895	connection::dnsv4_cb (time_watcher &w)	1210	dns_connection::time_cb (time_watcher &w)
896	{	1211	{
		1212	// servers have to be polled
		1213	if (THISNODE->dns_port)
		1214	return;
		1215
897	// check for timeouts and (re)transmit	1216	// check for timeouts and (re)transmit
898	tstamp next = NOW + 60;	1217	tstamp next = NOW + poll_interval;
899	dns_req *send = 0;	1218	dns_snd *send = 0;
900		1219
901	for (vector<dns_req *>::iterator i = vpn->dns_sndpq.begin ();	1220	for (vector<dns_snd *>::iterator i = vpn->dns_sndpq.begin ();
902	i != vpn->dns_sndpq.end ();	1221	i != vpn->dns_sndpq.end ();
903	++i)	1222	++i)
904	{	1223	{
905	dns_req r = i;	1224	dns_snd r = i;
906		1225
907	if (r->next <= NOW)	1226	if (r->timeout <= NOW)
908	{	1227	{
909	if (!send)	1228	if (!send)
910	{	1229	{
911	send = r;	1230	send = r;
912		1231
913	if (r->retry)//D
914	printf ("req %d:%d, retry %d\n", r->seqno, r->pkt->id, r->retry);
915	r->retry++;	1232	r->retry++;
916	r->next = NOW + r->retry;	1233	r->timeout = NOW + (r->retry * min_latency * TIMEOUT_FACTOR);
		1234
		1235	// the following code changes the query section a bit, forcing
		1236	// the forwarder to generate a new request
		1237	if (r->stdhdr)
		1238	{
		1239	//printf ("reencoded header for ID %d retry %d:%d:%d (%p)\n", htons (r->pkt->id), THISNODE->id, r->seqno, r->retry);
		1240	//encode_header ((char )r->pkt->at (6 2 + 1), THISNODE->id, r->seqno, r->retry);
		1241	}
917	}	1242	}
918	}	1243	}
919		1244	else
920	if (r->next < next)	1245	NEXT (r->timeout);
921	next = r->next;
922	}	1246	}
923		1247
924	if (!send	1248	if (!send)
		1249	{
		1250	// generate a new packet, if wise
		1251
		1252	if (!established)
		1253	{
		1254	if (vpn->dns_sndpq.empty ())
		1255	{
		1256	send = new dns_snd (this);
		1257
		1258	cfg.reset (THISNODE->id);
		1259	send->gen_syn_req ();
		1260	}
		1261	}
925	&& vpn->dns_sndpq.size () < MAX_OUTSTANDING)	1262	else if (vpn->dns_sndpq.size () < MAX_OUTSTANDING
926	{	1263	&& !SEQNO_EQ (rcvseq, sndseq - (MAX_WINDOW - 1)))
		1264	{
		1265	if (last_sent + send_interval <= NOW)
		1266	{
		1267	//printf ("sending data request etc.\n"); //D
		1268	if (!snddq.empty () \|\| last_received + 1. > NOW)
		1269	{
		1270	poll_interval = send_interval;
		1271	NEXT (NOW + send_interval);
		1272	}
		1273
927	send = new dns_req (this);	1274	send = new dns_snd (this);
928	send->gen_stream_req (dns_sndseq, dns_snddq);	1275	send->gen_stream_req (sndseq, snddq);
		1276	send->timeout = NOW + min_latency * TIMEOUT_FACTOR;
		1277
		1278	sndseq = (sndseq + 1) & SEQNO_MASK;
		1279	}
		1280	else
		1281	NEXT (last_sent + send_interval);
		1282	}
		1283
		1284	if (send)
929	vpn->dns_sndpq.push_back (send);	1285	vpn->dns_sndpq.push_back (send);
930
931	dns_sndseq = (dns_sndseq + 1) & SEQNO_MASK;
932	}	1286	}
933
934	tstamp min_next = NOW + (1. / (tstamp)MAX_RATE);
935		1287
936	if (send)	1288	if (send)
937	{	1289	{
938	dns_packet *pkt = send->pkt;	1290	last_sent = NOW;
939		1291	sendto (vpn->dnsv4_fd,
940	next = min_next;	1292	send->pkt->at (0), send->pkt->len, 0,
941		1293	vpn->dns_forwarder.sav4 (), vpn->dns_forwarder.salenv4 ());
942	sendto (vpn->dnsv4_fd, &((*pkt)[0]), pkt->len, 0, dns_si.sav4 (), dns_si.salenv4 ());
943	}	1294	}
944	else if (next < min_next)	1295
945	next = min_next;	1296	slog (L_NOISE, "DNS: pi %f si %f N %f (%d:%d %d)",
		1297	poll_interval, send_interval, next - NOW,
		1298	vpn->dns_sndpq.size (), snddq.size (),
		1299	rcvpq.size ());
		1300
		1301	// TODO: no idea when this happens, but when next < NOW, we have a problem
		1302	if (next < NOW + 0.001)
		1303	next = NOW + 0.1;
946		1304
947	w.start (next);	1305	w.start (next);
948	}	1306	}
949		1307
950	#endif	1308	#endif

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Comparing gvpe/src/vpn_dns.C (file contents): Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs. Revision 1.36 by pcg, Thu Mar 17 22:24:31 2005 UTC

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Comparing gvpe/src/vpn_dns.C (file contents):
Revision 1.8 by pcg, Fri Mar 4 03:43:09 2005 UTC vs.
Revision 1.36 by pcg, Thu Mar 17 22:24:31 2005 UTC